Plant root carbon inputs drive methane production in tropical peatlands.

Tropical peatlands are carbon-dense ecosystems that are significant sources of atmospheric methane (CH). Recent work has demonstrated the importance of trees as an emission pathway for CH from the peat to the atmosphere. However, there remain questions over the processes of CH production in these systems and how they relate to substrate supply.

Tropical forest clearance impacts biodiversity and function, whereas logging changes structure.

The impacts of degradation and deforestation on tropical forests are poorly understood, particularly at landscape scales. We present an extensive ecosystem analysis of the impacts of logging and conversion of tropical forest to oil palm from a large-scale study in Borneo, synthesizing responses from 82 variables categorized into four ecological levels spanning a broad suite of ecosystem properties: (i) structure and environment, (ii) species traits, (iii) biodiversity, and (iv) ecosystem functions. Responses were highly heterogeneous and often complex and nonlinear.

Microbial and mineral interactions decouple litter quality from soil organic matter formation.

Current understanding of soil carbon dynamics suggests that plant litter quality and soil mineralogy control the formation of mineral-associated soil organic carbon (SOC). Due to more efficient microbial anabolism, high-quality litter may produce more microbial residues for stabilisation on mineral surfaces. To test these fundamental concepts, we manipulate soil mineralogy using pristine minerals, characterise microbial communities and use stable isotopes to measure decomposition of low- and high-quality litter and mineral stabilisation of litter-C.

Vegetation type, not the legacy of warming, modifies the response of microbial functional genes and greenhouse gas fluxes to drought in Oro-Arctic and alpine regions.

Climate warming and summer droughts alter soil microbial activity, affecting greenhouse gas (GHG) emissions in Arctic and alpine regions. However, the long-term effects of warming, and implications for future microbial resilience, are poorly understood. Using one alpine and three Arctic soils subjected to in situ long-term experimental warming, we simulated drought in laboratory incubations to test how microbial functional-gene abundance affects fluxes in three GHGs: carbon dioxide, methane, and nitrous oxide.

Revealing the transfer pathways of cyanobacterial-fixed N into the boreal forest through the feather-moss microbiome.

Introduction: Biological N fixation in feather-mosses is one of the largest inputs of new nitrogen (N) to boreal forest ecosystems; however, revealing the fate of newly fixed N within the bryosphere (i.e. bryophytes and their associated organisms) remains uncertain.

Interactions between climate warming and land management regulate greenhouse gas fluxes in a temperate grassland ecosystem.

Greenhouse gas (GHG) fluxes from grasslands are affected by climate warming and agricultural management practices including nitrogen (N) fertiliser application and grazing. However, the interactive effects of these factors are poorly resolved in field studies. We used a factorial in situ experiment - combining warming, N-fertiliser and above-ground cutting treatments - to explore their individual and interactive effects on plant-soil properties and GHG fluxes in a temperate UK grassland over two years.

Do soil depth and plant community composition interact to modify the resistance and resilience of grassland ecosystem functioning to drought?

While the effect of drought on plant communities and their associated ecosystem functions is well studied, little research has considered how responses are modified by soil depth and depth heterogeneity. We conducted a mesocosm study comprising shallow and deep soils, and variable and uniform soil depths, and two levels of plant community composition, and exposed them to a simulated drought to test for interactive effects of these treatments on the resilience of carbon dioxide fluxes, plant functional traits, and soil chemical properties. We tested the hypotheses that: (a) shallow and variable depth soils lead to increased resistance and resilience of ecosystem functions to drought due to more exploitative plant trait strategies; (b) plant communities associated with intensively managed high fertility soils, will have more exploitative root traits than extensively managed, lower fertility plant communities.

Land-use changes alter soil bacterial composition and diversity in tropical forest soil in China.

Tropical forests, under pressure from human activities, are important reservoirs of biodiversity and regulators of global biogeochemical cycles. Land-use and management are influential drivers of environmental change and ecosystem sustainability. However, only limited studies have analysed the impacts of planting age and vegetation type under land-use change on soil microbial community in tropical forests simultaneously.

Imaging spectroscopy reveals the effects of topography and logging on the leaf chemistry of tropical forest canopy trees.

Logging, pervasive across the lowland tropics, affects millions of hectares of forest, yet its influence on nutrient cycling remains poorly understood. One hypothesis is that logging influences phosphorus (P) cycling, because this scarce nutrient is removed in extracted timber and eroded soil, leading to shifts in ecosystem functioning and community composition. However, testing this is challenging because P varies within landscapes as a function of geology, topography and climate.

Drought soil legacy overrides maternal effects on plant growth.

Maternal effects (i.e. trans-generational plasticity) and soil legacies generated by drought and plant diversity can affect plant performance and alter nutrient cycling and plant community dynamics.

Microbial responses to warming enhance soil carbon loss following translocation across a tropical forest elevation gradient.

Tropical soils contain huge carbon stocks, which climate warming is projected to reduce by stimulating organic matter decomposition, creating a positive feedback that will promote further warming. Models predict that the loss of carbon from warming soils will be mediated by microbial physiology, but no empirical data are available on the response of soil carbon and microbial physiology to warming in tropical forests, which dominate the terrestrial carbon cycle. Here we show that warming caused a considerable loss of soil carbon that was enhanced by associated changes in microbial physiology.

Spatial variability of organic matter properties determines methane fluxes in a tropical forested peatland.

Tropical peatland ecosystems are a significant component of the global carbon cycle and feature a range of distinct vegetation types, but the extent of links between contrasting plant species, peat biogeochemistry and greenhouse gas fluxes remains unclear. Here we assessed how vegetation affects small scale variation of tropical peatland carbon dynamics by quantifying in situ greenhouse gas emissions over 1 month using the closed chamber technique, and peat organic matter properties using Rock-Eval 6 pyrolysis within the rooting zones of canopy palms and broadleaved evergreen trees. Mean methane fluxes ranged from 0.

Plastic and genetic responses of a common sedge to warming have contrasting effects on carbon cycle processes.

Climate warming affects plant physiology through genetic adaptation and phenotypic plasticity, but little is known about how these mechanisms influence ecosystem processes. We used three elevation gradients and a reciprocal transplant experiment to show that temperature causes genetic change in the sedge Eriophorum vaginatum. We demonstrate that plants originating from warmer climate produce fewer secondary compounds, grow faster and accelerate carbon dioxide (CO ) release to the atmosphere.

Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier.

The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable 'cap' of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements.

Land use driven change in soil pH affects microbial carbon cycling processes.

Soil microorganisms act as gatekeepers for soil-atmosphere carbon exchange by balancing the accumulation and release of soil organic matter. However, poor understanding of the mechanisms responsible hinders the development of effective land management strategies to enhance soil carbon storage. Here we empirically test the link between microbial ecophysiological traits and topsoil carbon content across geographically distributed soils and land use contrasts.

Soil multifunctionality and drought resistance are determined by plant structural traits in restoring grassland.

It is increasingly recognized that belowground responses to vegetation change are closely linked to plant functional traits. However, our understanding is limited concerning the relative importance of different plant traits for soil functions and of the mechanisms by which traits influence soil properties in the real world. Here we test the hypothesis that taller species, or those with complex rooting structures, are associated with high rates of nutrient and carbon (C) cycling in grassland.

Microbes follow Humboldt: temperature drives plant and soil microbial diversity patterns from the Amazon to the Andes.

More than 200 years ago, Alexander von Humboldt reported that tropical plant species richness decreased with increasing elevation and decreasing temperature. Surprisingly, coordinated patterns in plant, bacterial, and fungal diversity on tropical mountains have not yet been observed, despite the central role of soil microorganisms in terrestrial biogeochemistry and ecology. We studied an Andean transect traversing 3.

Soil bacterial networks are less stable under drought than fungal networks.

Soil microbial communities play a crucial role in ecosystem functioning, but it is unknown how co-occurrence networks within these communities respond to disturbances such as climate extremes. This represents an important knowledge gap because changes in microbial networks could have implications for their functioning and vulnerability to future disturbances. Here, we show in grassland mesocosms that drought promotes destabilising properties in soil bacterial, but not fungal, co-occurrence networks, and that changes in bacterial communities link more strongly to soil functioning during recovery than do changes in fungal communities.

Widespread asymmetric response of soil heterotrophic respiration to warming and cooling.

Soil is the largest organic carbon (C) pool in terrestrial ecosystems. Periodic changes in environmental temperature occur diurnally and seasonally; yet, the response of soil organic matter (SOM) decomposition to varying temperatures remains unclear. In this study, we conducted a modified incubation experiment using soils from 16 forest ecosystems in China with periodically and continuously varying incubation temperature to investigate how heterotrophic respiration (R) responds to different temperature patterns (both warming and cooling temperature ranging between 5 and 30°C).

Predicting the structure of soil communities from plant community taxonomy, phylogeny, and traits.

There are numerous ways in which plants can influence the composition of soil communities. However, it remains unclear whether information on plant community attributes, including taxonomic, phylogenetic, or trait-based composition, can be used to predict the structure of soil communities. We tested, in both monocultures and field-grown mixed temperate grassland communities, whether plant attributes predict soil communities including taxonomic groups from across the tree of life (fungi, bacteria, protists, and metazoa).